Fuse part in semiconductor device and method for forming the same

ABSTRACT

A fuse part in a semiconductor device has a plurality of fuse lines extended along a first direction with a given width along a second direction. The fuse part includes a first conductive pattern having a space part formed in a fuse line region over a substrate, wherein portions of the first conductive pattern are spaced apart by the space part along the first direction. The fuse part includes a first insulation pattern formed over the space part, the first insulation pattern having a width smaller than a width of the first conductive pattern along the second direction and a thickness greater than a thickness of the first conductive pattern, and a second conductive pattern formed over the first insulation pattern, the second conductive pattern having a width greater than the width of the first insulation pattern along the second direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of U.S. patentapplication Ser. No. 12/344,174, filed Dec. 24, 2008, which claimspriority of Korean patent application number 10-2008-0030268, filed onApr. 1, 2008, which is incorporated herein by reference in its entirety.

BACKGROUND

When a semiconductor memory device is fabricated, one defective cell outof numerous micro cells results in the semiconductor memory device beingdiscarded as an inferior device because the semiconductor memory devicewill not be able to execute a sufficient level of performance as amemory. However, it is very inefficient yield-wise to discard the entiredevice for having few defective cells in the memory. Thus, redundancycells, which are installed beforehand in the memory, are currently beingused to perform a repair process for replacing the defective cells. Inthis way, yield is improved because the entire memory is resuscitated.The semiconductor memory device includes a fuse part which storesaddress information of defective cells in accordance with the connectingstate of a fuse to perform the repair process.

FIG. 1A illustrates a plan view of a fuse part in a typicalsemiconductor device. FIG. 1B illustrates a cross-sectional view takenalong a line A-A′ of the semiconductor device shown in FIG. 1A.

Referring to FIGS. 1A and 1B, a plurality of fuse lines 11 are formedover a semi-finished substrate 10. The fuse lines 11 are formed usingone of existing circuit lines, e.g., plate lines and metal lines, in thefuse part rather than using additional lines.

An insulation layer 12 is formed over the fuse lines 11. The insulationlayer 12 includes a fuse box 13 which represents a fuse open region. Thefuse box 13 is formed by selectively etching the insulation layer 12. Aportion of the insulation layer 12 remains to a certain thickness R_(ox)over the fuse lines 11 after the fuse box 13 is formed.

According to the typical repairing method, a laser is applied to thefuse lines 11 through the fuse box 13 after forming the fuse part to cutthe fuse lines 11. However, such repairing process shows the followinglimitations.

In order to successfully perform a fuse cutting process, the thicknessR_(ox) of the remaining insulation layer over the fuse lines has to bewithin appropriate range of values. However, the fuse cutting processoften fails because it is difficult to control the thickness R_(ox) dueto the large differences in the thickness of the remaining insulationlayer over the fuse lines formed over the wafer. Also, remnants areoften generated after the fuse cutting process, causing limitations.Furthermore, damages may occur in fuse lines adjacent to the fuse linesbeing cut.

SUMMARY

Embodiments of a fuse part in a semiconductor device and a method forforming the same improve the reliability and yield of the device byusing melted metal for fuse coupling instead of a typical fuse cuttingmethod during a repair process.

In accordance with an aspect of a fuse part in a semiconductor device, aplurality of fuse lines extends along a first direction with a givenwidth along a second direction. The fuse part includes: a firstconductive pattern having a space part formed in a fuse line region overa substrate, wherein portions of the first conductive pattern are spacedapart by the space part along the first direction; a first insulationpattern formed over the space part, the first insulation pattern havinga width smaller than a width of the first conductive pattern along thesecond direction and a thickness greater than a thickness of the firstconductive pattern; and a second conductive pattern formed over thefirst insulation pattern, the second conductive pattern having a widthgreater than the width of the first insulation pattern along the seconddirection.

In accordance with another aspect, a method for forming a fuse part in asemiconductor device, the fuse part having a plurality of fuse linesextended along a first direction with a given width along a seconddirection, includes: forming a first conductive pattern having a spacepart in a fuse line region over a substrate, wherein portions of thefirst conductive pattern are spaced apart by the space part along thefirst direction; forming an inter-layer insulation layer over theresultant structure; etching the inter-layer insulation layer using amask pattern to expose the space part, the mask pattern having openingswith a width smaller than a width of the space part along the seconddirection; burying an insulation layer over the etched region of theinter-layer insulation layer to form a first insulation pattern; forminga second conductive pattern over the first insulation pattern and theinter-layer insulation layer, the second conductive pattern covering thespace part; and removing remaining portions of the inter-layerinsulation layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a plan view of a fuse part in a typicalsemiconductor device.

FIG. 1B illustrates a cross-sectional view taken along a line A-A′ ofthe semiconductor device shown in FIG. 1A.

FIGS. 2A to 8B are plan and cross-sectional views of a fuse part in asemiconductor device to describe a method for forming the same inaccordance with a first embodiment.

FIGS. 9A to 11B are plan and cross-sectional views of a fuse part in asemiconductor device to describe a method for forming the same inaccordance with a second embodiment.

DESCRIPTION OF EMBODIMENTS

FIGS. 2A to 8B are plan and cross-sectional views of a fuse part in asemiconductor device to describe a method for forming the same inaccordance with a first embodiment. FIGS. 2A, 3A, 4A, 5A, 6A, and 7A areplan views of the fuse part. FIGS. 2B, 3B, 4B, 5B, 6B, and 7B arecross-sectional views of the fuse part taken along a line A-A′. FIGS.2C, 3C, 4C, 5C, 6C, and 7C are cross-sectional views of the fuse parttaken along a line B-B′.

Hereafter, the direction along the length of fuse lines are referred toas a first direction and the direction intersecting the first directionalong the width of the fuse lines is referred to as a second directionfor convenience of description.

Referring to FIGS. 2A to 2C, fuse lines 21 are formed in regionspredetermined for fuse lines over a semi-finished substrate 20. The fuselines 21 are formed in a manner that a central portion of the fuse lines21 is cut off along the first direction so that two portions of the fuselines 21 are spaced out from each other. The portions where the fuselines 21 are cut off, that is, the portions where the fuse lines 21 donot exist in the regions predetermined for the fuse lines, are referredto as space parts S for convenience of description. The width of thespace parts S along the first direction is represented with referencedenotation L1. The width of the space parts S along the second directionis represented with reference denotation W1. The width of the spaceparts S along the second direction is substantially the same as thewidth of the fuse lines 21. The thickness of the fuse lines 21 isrepresented with reference denotation T1. The fuse lines 21 may beformed using lower metal lines from multiple layers of metal lines.

Referring to FIGS. 3A to 3C, an oxide-based layer is formed as aninter-layer insulation layer over the fuse lines 21. The oxide-basedlayer is formed to a thickness to sufficiently cover the fuse lines 21.For instance, in one embodiment, the oxide-based layer is formed toapproximately 6,000 Å.

Although not illustrated, a photoresist pattern is formed over theoxide-based layer to form a subsequent nitride pattern. The photoresistpattern has openings which expose the space parts S. In someembodiments, the width of the openings along the second direction issmaller than W1 of the space parts S. The width of the openings alongthe first direction may be larger than L1 of the space parts S.

The oxide-based layer is etched using the photoresist pattern as an etchmask to form trenches T in the oxide-based layer and thereby forming anoxide-based pattern 22. A nitride-based layer is buried in the trenchesT to form nitride-based patterns 23. Corresponding to the openings ofthe photoresist pattern, the width of the nitride-based patterns 23along the second direction, represented with reference denotation W2, issmaller than W1 of the space parts S. Also, the width of thenitride-based patterns 23 along the first direction, represented withreference denotation L2, may be larger than L1 of the space parts S.

Referring to FIGS. 4A to 4C, metal patterns 24 are formed over thenitride-based patterns 23 and the oxide-based pattern 22 to cover thespace parts S. The metal patterns 24 may be formed using upper metallines rather than the metal lines forming the fuse lines 21 frommultiple metal lines.

The width of the metal patterns 24 along the second direction asrepresented with reference denotation W3 are in some embodiments, largerthan W2 of the nitride-based patterns 23. For instance, W3 of the metalpatterns 24 may be substantially the same as W1 of the space parts S.Also, the width of the metal patterns 24, along the first direction asrepresented with reference denotation L3, may be larger than L1 of thespace parts S.

Referring to FIGS. 5A to 5C, a wet dip process is performed to removeexposed portions of the oxide-based pattern 22 using a mask which is thesame as a mask for forming a subsequent fuse box.

As a result, structures including the fuse lines 21 spaced at thecenter, the nitride-based patterns 23 formed in the space parts S,having the second direction width W2 smaller than the second directionwidth W1 of the space parts S and a thickness larger than the thicknessT1 of the fuse lines 21, and the metal patterns 24 formed over thenitride-based patterns 23, having the second direction width W3 largerthan the second direction width W2 of the nitride-based patterns 23 areformed. Because the second direction width W3 of the metal patterns 24is larger than the second direction width W2 of the nitride-basedpatterns 23, empty spaces S′ (shown in FIG. 5C) are formed below themetal patterns 24 in such structures due to the width difference.

Referring to FIGS. 6A to 6C, a spacer nitride layer is formed over theresultant structure. A dry blanket etch process is performed on thespacer nitride layer to form nitride spacers 25 on sidewalls of themetal patterns 24 and regions below the metal patterns 24. The regionsbelow the metal patterns 24 include the empty spaces S′ formed by thewidth difference, i.e., the difference between W3 and W2. The emptyspaces S′ are maintained during the formation of the nitride spacers 25due to the deposition characteristics of nitride. The nitride spacers 25are formed to prevent the metal patterns 24 from affecting adjacentfuses when the metal patterns 24 melt during a subsequent repairprocess.

Referring to FIGS. 7A to 7C, an insulation layer is formed over theresultant structure including the nitride spacers 25. The insulationlayer is selectively etched using a mask for forming a fuse box to forma fuse box 27. Reference numeral 26 refers to a patterned insulationlayer 26. When etching the insulation layer to form the fuse box 27, theinsulation layer is etched to a depth lower than the upper surface ofthe metal patterns 24 so that the upper surface of the metal patterns 24are sufficiently exposed. Thus, a fuse part is formed in accordance withthe first embodiment.

A method for repairing in the fuse part is described as follows.

Referring to FIG. 8A, a laser is applied through the fuse box 27 to themetal pattern 24 formed over the desired fuse line 21 to be coupled. Thelaser is applied at a melting temperature for metal included in themetal pattern 24 so that the metal pattern 24 may melt.

Referring to FIG. 8B, when the metal pattern 24 melts, the metal of themetal pattern 24 flows into the empty spaces S′ which was formed by thewidth difference between the nitride-based pattern 23 and the metalpattern 24 along the second direction. Accordingly, the two spaced outportions of the fuse line 21 are mutually coupled by the melted metal ofthe metal pattern 24. Reference numerals 23A and 24A represent aremaining nitride-based pattern 23A and a melted metal pattern 24A.

Accordingly, limitations caused during a typical repair process using afuse cutting method may not occur because the repair process isperformed by coupling the divided fuse lines using melted metal.

In the fuse part structure described in the first embodiment of thepresent invention, the repair process may be performed with more ease byadjusting the shape of the fuse lines, the width of the nitride-basedpatterns along the first and second directions, the width of the metalpatterns along the first and second directions, and the thickness of thenitride-based patterns. A method for forming a fuse part where the shapeof fuse lines is altered is described as follows.

FIGS. 9A to 11B are plan and cross-sectional views of a fuse part in asemiconductor device to describe a method for forming the same inaccordance with a second embodiment. FIGS. 9A, 10A, and 11A are planviews of the fuse part. FIGS. 9B, 10B, and 11B are cross-sectional viewsof the fuse part taken along a line C-C′. In this second embodiment,descriptions which overlap with FIGS. 2A to 7C in the first embodimentare omitted. The descriptions in the second embodiment focus on thedifference with FIGS. 2A to 7C in the first embodiment.

Hereafter, the direction along the length of fuse lines are referred toas a first direction and the direction intersecting the first directionalong the width of the fuse lines is referred to as a second directionfor convenience of description.

Referring to FIGS. 9A and 9B, fuse lines 31 are formed in regionspredetermined for fuse lines over a semi-finished substrate 30. The fuselines 31 are formed in a manner that a central portion of the fuse lines31 is cut off along the first direction so that two portions of the fuselines 31 are spaced out from each other. This description issubstantially the same as the description in the first embodiment. Inthe second embodiment, each cut and spaced apart portion of the fuselines 31 is formed to have two isolated lines and a space between thetwo isolated lines along the second direction.

When forming the fuse lines 21 in the first embodiment, it may bedifficult to mutually couple the spaced apart fuse line 21 during thelaser application if the width of the space parts S is too large alongthe first direction. On the other hand, if the width of the space partsS is too small along the first direction, it may be difficult to securea process margin during the subsequent processes, e.g., for forming thenitride-based patterns 23 and the metal patterns 24. Thus, it is moredesirable to form the fuse lines 31 in the shape shown in the secondembodiment.

Because the fuse lines 31 are formed in a shape different from that inthe first embodiment, space parts S1 are formed in a cross shape ratherthan a quadrangular shape like that of the space parts S in the firstembodiment.

Thus, the width of the space parts S1 along the first direction is notuniform as that of the space parts S in the first embodiment. The widthof the space parts S1 along the first direction between the two cutlines of the fuse lines 31 is smaller and the width of the space partsS1 along the first direction at the space between the two lines islarger.

The width of the space parts S1 along the first direction between thetwo cut lines of the fuse lines 31 is referred to as a minimum firstdirection width B1 of the space parts S1. The width of the space partsS1 along the first direction at the space between the two lines of thefuse lines 31 is referred to as a maximum first direction width B2 ofthe space parts S1.

Reference denotation W1′ represents the width of the fuse lines 31 alongthe second direction. Reference denotations A1 and A3 represent thewidth of each of the two cut lines of the fuse lines 31 along the seconddirection. Reference denotation A2 represents the width of the spacebetween the two lines of the fuse lines 31 along the second direction.

For instance, when W1′ of the fuse lines 31 is approximately 0.5 μm, A1and A3 of the two lines of the fuse lines 31 are approximately 0.2 μmeach and A2 of the space between the two lines is approximately 0.1 μm.That is, a ratio of A1:A2:A3 may be approximately 2:1:2.

Referring to FIGS. 10A and 10B, an oxide-based layer is formed over theresultant structure having the fuse lines 31. The oxide-based layer isformed to a thickness to sufficiently cover the fuse lines 31.

Although not illustrated, a photoresist pattern is formed over theoxide-based layer to form a subsequent nitride pattern. The details ofthe photoresist pattern are substantially the same as the description inthe first embodiment. The photoresist pattern has quadrangular openingscorresponding to portions where the space parts S1 are formed. In someembodiments, the width of the openings along the second direction issmaller than W1′ of the fuse lines 31. Furthermore, in some embodiments,the width of the openings along the second direction must be smallerthan W1′ of the fuse lines 31. For instance, the width of the openingsalong the second direction is formed to a width that exposes a portionof each of the two lines of the fuse lines 31. The width of the openingsalong the first direction may be larger than the minimum first directionwidth B1 of the space parts S1 and smaller than the maximum firstdirection width B2 of the space parts S1.

The oxide-based layer is etched using the photoresist pattern as an etchmask to form trenches T′ in the oxide-based layer and thereby forming anoxide-based pattern 32. A nitride-based layer is buried in the trenchesT′ to form nitride-based patterns 33. Corresponding to the openings ofthe photoresist pattern, the width of the nitride-based patterns 33along the second direction, represented with reference denotation W2′,is smaller than W1′ of the fuse lines 31. For instance, W2′ of thenitride-based patterns 33 is formed to a width that covers a portion ofeach of the two lines of the fuse lines 31. Also, the width of thenitride-based patterns 33 along the first direction, represented withreference denotation L2′, may be larger than the minimum first directionwidth B1 of the space parts S1 and smaller than the maximum firstdirection width B2 of the space parts S1.

Referring to FIGS. 11A and 11B, metal patterns 34 are formed over thenitride-based patterns 33 and the oxide-based pattern 32 to cover thespace parts S′.

The width of the metal patterns 34 along the second direction,represented with reference denotation W3′, is, in some embodiments,larger than W2′ of the nitride-based patterns 33, and in someembodiments must be larger than W2′. For instance, W3′ has substantiallythe same width as W1′ of the fuse lines 31. Also, the width of the metalpatterns 34 along the first direction, represented with referencedenotation L3′, may be substantially the same as L2′ of thenitride-based patterns 33.

Details of subsequent processes are substantially the same as thatdescribed in FIGS. 5A to 7C in the first embodiment. Thus, a fuse partis formed in accordance with the second embodiment. Furthermore, amethod for repairing in this fuse part structure according to the secondembodiment is substantially the same as that described in FIGS. 8A and8B.

In other words, the fuse part in accordance with the second embodimenthas a structure that allows an easier repair process because the cutends of the fuse lines have two isolated lines, adjusting the width ofthe nitride-based patterns and the metal patterns.

Disclosed embodiments relate to a fuse part in a semiconductor deviceand a method for forming the same, wherein metal is melted to couplefuses, thus improving the reliability and yield of the device.

While specific embodiments have been described, it will be apparent tothose skilled in the art that various changes and modifications may bemade without departing from the spirit and scope of the followingclaims.

What is claimed is:
 1. A method for forming a fuse part in asemiconductor device, the fuse part having a plurality of fuse linesextended along a first direction with a given width along a seconddirection, the method comprising: forming a first conductive patternhaving a space part in a fuse line region over a substrate, whereinportions of the first conductive pattern are spaced apart by the spacepart along the first direction; forming an inter-layer insulation layerover first conductive pattern; etching the inter-layer insulation layerusing a mask pattern to expose the space part, the mask pattern havingopenings with a width smaller than a width of the space part along thesecond direction; burying an insulation layer in the etched region ofthe inter-layer insulation layer to form a first insulation pattern;forming a second conductive pattern over the first insulation patternand the inter-layer insulation layer, the second conductive patterncovering the space part; and removing remaining portions of theinter-layer insulation layer.
 2. The method of claim 1, furthercomprising, after removing the remaining portions of the inter-layerinsulation layer: forming a spacer material layer; and performing a dryblanket etch on the spacer material layer to form spacers over sidewallsof the second conductive pattern and an empty space below the secondconductive pattern.
 3. The method of claim 2, further comprising afterperforming the dry blanket etch to form the spacers: forming a secondinsulation layer; and selectively etching the second insulation layer toform a fuse box exposing the second conductive pattern.
 4. The method ofclaim 1, wherein the first conductive pattern comprises a lower metalline, and the second conductive pattern comprises an upper metal line.5. The method of claim 1, wherein the first insulation pattern comprisesa nitride-based layer and the inter-layer insulation layer comprises anoxide-based layer.
 6. The method of claim 1, wherein removing remainingportions of the inter-layer insulation layer comprises performing a wetdip process.
 7. The method of claim 2, wherein the first insulationpattern and the spacers comprise a nitride-based layer.
 8. The method ofclaim 1, wherein a width of the openings along the first direction isgreater than a width of the space part along the first direction.
 9. Themethod of claim 1, wherein a width of the second conductive patternalong the first direction is greater than a width of the space partalong the first direction.
 10. The method of claim 1, wherein ends ofthe spaced apart first conductive pattern formed on both sides of thespace part have two lines isolated along the second direction.
 11. Themethod of claim 10, wherein the openings along the second direction havewidths formed to expose a portion of each of the two lines, and theopenings along the first direction have a width ranging between aminimum width and a maximum width of the space part along the firstdirection.
 12. The method of claim 10, wherein a width of the secondconductive pattern along the second direction is substantially the sameas the width of the space part along the second direction, and a widthof the second conductive pattern along the first direction rangesbetween a minimum width and a maximum width of the space part along thefirst direction.